The invention relates to a submersible pump, and to a method for producing a submersible pump, comprising a casing, with a suction-side inlet opening, a pressure-side outlet opening and a through-passage for electric lines, and also comprising an electronics unit, an electric motor, a pressure chamber and a pump unit.
Submersible pumps are a generic type of pump designed for various areas of use and co-ordinated with requirements in each case. The essential factor is the possibility of submerging the pump into the fluid which is to be delivered. One specific embodiment requires that the pump can be placed in a borehole or well. Since boreholes or wells, in particular those which are very deep, are very costly, adaptation to the borehole or well is a significant feature of such a pump.
U.S. Pat. No. 4,966,532 discloses a submersible motor pump in which the inlet, pump and outlet are arranged axially in a row. Individual components are surrounded by a common shell which is subdivided into a first region, which encloses the motor, and a second region, which encloses the pump. The two regions are connected by a connecting element, which defines both the distance of the components from the inner wall of the casing and the axial position.
EP 0 746 683 B1 discloses a submersible pump of the generic type in which the essential individual components of the pump are arranged axially. The suction-side inlet cover, the pump impeller, the motor and the pressure-side outlet cover are located in a single line. These individual components are accommodated in a tubular shell, wherein the fluid delivered is guided to the pressure-side outlet opening through a gap between the motor and the casing. The gap between the tubular shell and the motor casing is defined by an elastomeric pads. The motor is installed on the suction-side inlet cover, which also contains the pump impeller. The pressure-side outlet cover is connected merely to the tubular shell.
It is an object of the invention to provide a submersible pump of the generic type which allows straightforward assembly and repair of the submersible pump.
The solution provides a submersible pump in which the electronics unit, the electric motor, the pressure chamber and the pump unit can be preassembled to form an insert, wherein the preassembled insert is supported at one end of the casing and an axial clamping and/or fastening system is provided at the opposite end of the casing. The electronics unit may comprise both power electronics and signal electronics.
The construction of the submersible pump according to the invention allows the preassembled individual components to be placed in position prior to being introduced into the surrounding casing. It is also possible for the surrounding casing to be configured in a single part or piece, and this improves the sealing against the ingress of fluid. The clamping and fastening system makes it possible to provide the insert with prestressing.
According to one configuration of the submersible pump according to the invention, the clamping and/or fastening system can be released. This has the advantage that the insert can be removed from the surrounding casing for inspection purposes. Thereafter, it can be re-inserted and fixed in the casing anew by the clamping and/or fastening system.
It is particularly advantageous to configure the clamping and/or fastening system as a taper lock clamping bushing, this making it possible to establish a force-fitting connection which is centered axially.
In a further advantageous configuration, all the components of the insert are provided with fixed or releasable devices for providing support, in particular radial support, against the casing. The devices serve for transporting heat from the motor to the surrounding casing and, at the same time, support the insert assembly on the casing at a precisely defined distance therefrom, wherein displacement of individual components during operation of the pump is prevented.
It is advantageous for a bearing for supporting the insert, in particular for supporting the same in a centered manner, to be provided in the region of the pressure-side outlet opening. The insert can be fitted directly into this bearing by means of a guide during assembly. The centering makes it easier to establish the defined prestressing of the insert in relation to the surrounding casing.
The motor is advantageously a synchronous motor, in particular a synchronous motor equipped with permanent magnets. These motors are energy-efficient, easy to operate and robust. If the submersible motor pump is used as a pump for drilling boreholes or wells, then it is imperative for the technology used to be robust, since the pump has to be raised out of the borehole or well for repair purposes.
In one configuration of the invention, the pump is configured as a centrifugal pump. It is advantageous here that large delivery volumes with a variable delivery height are possible. It is also possible, in the case of centrifugal pumps, to deliver small quantities of sand.
In a further embodiment, the pump is configured as a positive-displacement pump, in particular as an eccentric screw pump. This self-priming pump allows considerable delivery heights and variable delivery volumes along with low-pulsation operation.
In a further embodiment, a pressure line is provided on the pressure-side outlet opening, a retaining means for a traction mechanism of the submersible pump being integrated in said pressure line. In particular, the outlet opening itself can function as a retaining means. For inspection purposes, the pump can be raised out of the borehole or well by way of the traction mechanism. This simplifies the assembly of the pump on site, in particular in a borehole or well.
It is a further object of the invention to provide a method for producing a submersible pump of the construction described above.
The solution provides a method for producing and for assembling a submersible pump of the construction described above, wherein in a first step an insert is preassembled from an electronics unit, an electric motor, a pressure chamber and a pump unit, in a second step the insert is introduced into a casing, the insert being centered in the casing, and in a third step the insert is braced and fastened in the casing by a clamping and/or fastening system. The preassembly allows precise positioning of the individual components prior to the insert being introduced into the surrounding casing. If the insert is pushed into the surrounding casing, for example, on the suction side, then the devices for maintaining a fixed distance between the insert and the surrounding casing center the insert and the bearing on the pressure side and defines the precise position of the insert. The clamping system makes it possible for the insert to be subjected to prestressing. The fastening system secures the insert in the surrounding casing. If use is made of a taper lock fastening system, then the clamping assembly can be braced freely at the suction-side end of the surrounding tube without any further provision, for example holes or threads, having to be made there. The fastening of the insert can be released for inspection purposes. If the length of the insert should be changed slightly during the inspection, then the insert can be fastened in the surrounding casing again using the same fastening system.
Further configurations can be gathered from combining what has been presented thus far, and will therefore not be explained to any further extent here.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.